Alzheimer’s disease is a progressive degenerative disorder that becomes worse over time. It involves a gradual loss of memory, as well as changes in behavior, thinking, and language skills.

Alzheimer’s disease is the most common form of dementia. It affects more than 5 million people in the United States.

Although every person experiences Alzheimer’s differently, the way in which the disease progresses can be grouped into a series of stages.

It is important to make sure that someone with dementia lives well with the condition and that their needs are met, rather than focusing on what stage they might be in.

How quickly does Alzheimer’s disease progress?

Alzheimer’s seems to develop slowly compared with other types of dementia, but the rate of progression varies between individuals.

The average life expectancy for a person with this disease is 8-10 years after diagnosis, but people can live with Alzheimer’s for 20 years or more.

Several factors can affect disease progression. These include:

Age: People with Alzheimer’s symptoms that develop before age 65 years may have faster progression

Genes: A person’s genes may affect progression rate

Physical health: People with poorly managed heart conditions or diabetes, who have had several strokes, or have repeated infections, may deteriorate quicker

Keeping active, being involved in activities, and getting regular exercise may help the individual to maintain their abilities for longer.

Other important factors include:

Maintaining a healthy diet

Getting enough sleep

Taking all prescribed medication correctly

Quitting smoking

Not drinking too much alcohol

Going to regular check-ups

If a person with Alzheimer’s disease experiences a sudden change in abilities or behavior, they could have another health problem or an infection. It is important to seek advice from a doctor as soon as possible.

Stages of Alzheimer’s disease

Looking at Alzheimer’s in stages can give a clearer idea of the changes that could occur.

Stages are a rough guide. The symptoms a person has, and when they appear, will vary. There are several different ways of mapping Alzheimer’s disease. Some people refer to seven stages, while others refer to just three.

This article, however, will look at five stages of Alzheimer’s disease:

The dementia noted in stages 3 to 5 describes the set of symptoms that affect memory, thinking, problem-solving or language, and they are severe enough to affect daily life

The average time between the onset of Alzheimer’s symptoms and reaching a diagnosis is approximately 2.8 years.

Stage 1: Preclinical Alzheimer’s disease

The functional changes that are associated with Alzheimer’s are thought to begin years, or even decades, before diagnosis.

This long phase is known as the preclinical stage of Alzheimer’s disease. During this stage, there will not be any noticeable clinical symptoms.

Although there are no noticeable symptoms in the preclinical stage, imaging technologies can spot deposits of a protein called amyloid beta.

In people with Alzheimer’s disease, this protein clumps together and forms plaques. These protein clumps may block cell-to-cell signaling and activate immune system cells that trigger inflammation and destroy disabled cells.

There are other biological markers, or biomarkers, that show an increased risk of disease, as well as genetic tests that can detect if a person does have an increased risk.

Using imaging technology to locate amyloid beta clumps, biomarker detection, and genetic testing could all be important in the future as new Alzheimer’s treatments are developed.

Researchers are studying this preclinical stage to work out which factors can predict the risk of progression from normal cognition to stage 2 of Alzheimer’s progression, which involves mild cognitive impairment.

Researchers are also hoping that their studies will help people with Alzheimer’s get treated at a much earlier stage.

Disease-modifying therapies may be most effective in the more initial stages of Alzheimer disease, and they could slow disease progression.

Stage 2: Mild cognitive impairment due to Alzheimer’s disease

Mild cognitive impairment occurs between the cognitive decline that is expected as a normal part of aging, and the most severe decline of dementia.

A person with mild cognitive impairment may notice subtle changes in their thinking and their ability to remember things. They may exhibit memory lapses when it comes to recent conversations they have had, recent events, or appointments they have been to.

However, changes to memory and thinking at this stage are not serious enough to cause problems with day-to-day life or usual activities.

As people age, it is normal for forgetfulness to increase slightly, or for individuals to take longer to think of a word or remember a name. If the problem is more severe, it could be a sign of mild cognitive impairment.

Symptoms of mild cognitive impairment include:

Forgetting things more often

Forgetting appointments, conversations, or recent events

Inability to make decisions or feeling overwhelmed when doing so

Becoming increasingly unable to judge the time or sequence of steps to complete a task

Having difficulty finding the correct words to describe an object or idea

Getting lost or misplacing items

Stage 4: Moderate dementia due to Alzheimer’s disease

During the stage of moderate dementia due to Alzheimer’s disease, the person becomes increasingly confused and forgetful. They may need help with daily tasks and assistance with looking after themselves.

Needing complete assistance with personal care, eating, dressing, and using the bathroom

Failure to walk without help, unable to sit, or hold head up

Rigid muscles and abnormal reflexes

Loss of the ability to swallow, inability to control bladder and bowel movements

A person with severe Alzheimer’s disease has a high chance of dying from pneumonia. Pneumonia is a common cause of death in those with Alzheimer’s because as the person loses the ability to swallow, food and beverages can enter the lungs and cause infection.

Other common causes of death among people with Alzheimer’s disease can include dehydration, malnutrition, and other infections.